From: | Enrico Sirola <enrico(dot)sirola(at)gmail(dot)com> |
---|---|
To: | pgsql-performance(at)postgresql(dot)org |
Subject: | 8.3 write performance |
Date: | 2008-03-12 15:25:29 |
Message-ID: | 2226A814-87D8-4531-AC26-D1E7B44227C0@gmail.com |
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Thread: | |
Lists: | pgsql-performance |
Hello,
(you could receive this message twice - I have some email issues sorry)
I'm setting up a new DB with Centos 5 (amd64) + postgresql 8.3
installed from the pgsql yum repository. This is a host dedicated to
postgresql. From the benchmarks I found here and there on the web, and
having digged a bit on the ML, it seems that I could expect something
similar to 4000 tps with pgbench.
The host is a HP DL580 G5, 8GB of RAM with 8x146G 10k SAS disks and
2x2.4GHz quad-code intel xeons, with a battery-backed P400/512MB
controller.
I tried two disk layout configurations:
- raid 1 system
- raid 1 for WAL
- raid 10 (4 disks) for data
and
- raid 1 system
- raid 10 (6 disks) WAL+data
the FS is ext3 (without lvm) for all the db-related partitions,
created with the following options
-b 4096 -E stride=32 -j -m 10 -T largefile
(the array stripe size is 128k) and mounted with
noatime,data=writeback
pgbench reports circa 2000 tps with a number of clients ranging from 2
to 12 and starts decreasing afterwards with the number of clients, for
example I get 1200 tps with 50 clients.
The relevant configuration items of the DB is like in the following
(default values are not shown)
------------------------------------
max_connections = 100
shared_buffers = 2GB
temp_buffers = 128MB
work_mem = 8MB
maintenance_work_mem = 128MB
max_fsm_pages = 1000000
bgwriter_delay = 200ms
fsync = on
synchronous_commit = on
wal_sync_method = fdatasync
wal_buffers = 1024kB
commit_delay = 100
checkpoint_segments = 128
effective_cache_size = 5GB
constraint_exclusion = on
--------------------------------------
I'm a bit worried about this 2k tps limit I hit regardless of the disk
layout, and also by the fact that it seems someone else reported to
have much better figures (4ktps) with similar hardware. Does anyone
have hints/suggestions/advices about what could be further optimized?
Thanks a lot for your help,
Enrico
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